1. Technical Field
The present disclosure relates to hand held surgical stapling apparatus. More particularly, the present disclosure relates to retraction mechanism for hand held surgical stapling apparatus.
2. Background of Related Art
Some surgical apparatus are capable of fastening tissue layers. In general, surgical fastening apparatus include two elongated jaw members designed for capturing or clamping tissue. One jaw member typically contains a staple cartridge. The staple cartridge houses a plurality of staples. Typically, the staple cartridges include at least two lateral rows of retention slots. Each retention slot is adapted to receive a staple. The other jaw member has an anvil that defines a surface for faulting the staple legs as the staples are driven from the staple cartridge. The stapling operation is usually effected by cam members that translate through the staple cartridge. These cam members are connected to a firing drive that moves from a proximal position to a distal position when a user actuates the surgical stapling apparatus. Upon actuation of the surgical stapling apparatus, the firing drive moves in a distal direction and causes the cam members to move from a proximal position to a distal position through the staple cartridge. While the cam members translate through the staple cartridge, these cam members sequentially act on staple pushers positioned along the staple cartridge to eject the staples from the staple cartridge. The surgical stapling apparatus may further include a knife operatively attached to the cam members and positioned between two rows of staple slots. Alternatively, the knife may be attached to the drive member rather than the cam member. Since the knife is operatively attached to the cam members, the knife moves from proximal position to a distal position, while the cam members translate from a proximal portion to a distal portion of the staple cartridge. As the knife moves through the staple cartridge, it cuts or opens tissue positioned between the jaw members.
Another surgical stapling apparatus applies a double row of staples on each side of the incision. This surgical stapling apparatus has a disposable loading unit wherein a cam member moves from a proximal position to a distal position through an elongate guide path between two sets of staggered staple carrying grooves. Staple drive members are located within the grooves and are positioned in such a manner so as to be contacted by the longitudinally moving cam member. The staple members eject the staples in the staple cartridge as the cam member moves axially along the elongate guide path.
Each of the apparatus described hereinabove is designed for use in conventional surgical procedures wherein surgeons have direct manual access to the operative site. In endoscopic or laparoscopic procedures, however, surgery is performed through a small incision or through a narrow cannula inserted through small entrance wounds in the skin. Endoscopic surgical stapling devices have been developed to address the specific needs of endoscopic and laparoscopic surgical procedures. A few examples of endoscopic surgical stapling devices are disclosed in U.S. Pat. Nos. 5,307,976; 5,312,023; 5,326,013; 5,332,142; and 6,241,139, the entire contents of each of which are incorporated herein by reference.
As discussed above, the cam members of the surgical stapling apparatus discussed above are operatively connected to a firing drive. Consequently, a distal motion of the firing drive causes the cam members to move in a distal direction. The surgical stapling apparatus devices discussed above may further include a retraction mechanism to return the firing drive to a proximal position. Given that the cam members are coupled to the firing drive, the retraction mechanism also moves the cam members (along with the firing drive) to a proximal position. The retraction mechanism includes a pair of retractor knobs movably positioned along a barrel portion of a handle assembly. The retraction knobs are manually pulled proximally to return the firing drive to its proximal position after firing the surgical stapling apparatus.
Other endoscopic stapling apparatus include powered retraction mechanisms. For instance, U.S. patent application Ser. No. 11/784,804, filed Apr. 9, 2007, the entire contents of which is hereby incorporated by reference, discloses a surgical stapling apparatus including a powered retraction mechanism. An embodiment of this retraction mechanism includes a motor operatively associated with a pulley and a slip clutch. The pulley is configured to retract the firing drive of the surgical stapling apparatus once the slip clutch moves to its engaged position.
The surgical apparatus described above have provided significant clinical benefits. Nonetheless, improvements to these instruments are possible. For instance, it would be beneficial to provide a more compact retraction mechanism for surgical apparatus.